An example of functions which have to be controlled and supervised in a weaving machine is e.g. the tension in the yarn during the weaving procedure. The tension can be modified by means of yarn brakes with actuates the yarn frictionally. Spool shifts and changing over yarn feed elements is another example for controlling operations concerned with the yarn. A third example is operations for weft insertion, threading up, drawing in, etc. The invention is useful i.e., on and for weaving machines/i.e., looms of the type rapier (=gripper the term of (which is used below). In a weaving loom it is today typically necessary to be able to initiate 800-1200 picks/minute.
It is previously known to provide elements in a textile machine with a computer or microprocessor for control of functions or units.
The units exist in different types and variants and have to be capable of being applied to different types and variants of weaving machines. The electrical connection of the feeders to one another and to the controlling or supervising system of the weaving machine has hitherto been brought about in a different manner for each connection case. The connection is in general effected in terminal boxes in which a number of connection wires must be assigned their positions which are fixed for the connection case. There is a need for more standardized kinds of connection.
The weaving machine and feed elements represent a large number of functions which on the one hand have to be capable of being individually controlled and supervised and on the other have to be mutually interrelated to achieve an optimum functioning of the weaving machine. This means that the supervising and/or controlling system must be able to work rapidly and functionally reliably with e.g. short reaction times for yarn breaks, faults in the weaving pattern etc.
The use of a computerized system opens up the possibility of storing a large amount of information which can be used for the control and the supervision of elements/the machine. Signal-processing units, transmitters and drive units can be used in large numbers. A large range of different variants and solutions is offered to clients who wish to adapt their machinery according to the case selected for the occasion, which means that solutions which permit simple modifications of existing equipment are attractive.
Considering the large amount of information and the requirement for accuracy of the information, the transmission in the computerized system must take place accurately and with such speed that events which have occurred in the system are detected sufficiently rapidly in the places where the events which have occurred are to be acted upon in some respect. For each transmission case, the principle which applies is that a sequence of events is to be carried out. This sequence must in general be synchronized in some way, which can be achieved with the aid of, on the one hand, a run initiation signal (trigger signal) which gives rise to a certain sequence being carried out in the system, and, on the other, an acknowledgement signal which issues acknowledgement that an effected sequence is performed. In certain cases, an acknowledgement signal can be such that it directly initiates a new run. Alternatively, acknowledgements can be collected at a suitable place in the system in order to initiate a new run, taking as a starting point these together with some other criterion.
In order that the transmission be effective, it must have the following characteristics. The signal is to reach its destination within a stipulated time. Often it is a matter of a maximum permissible time between event and action, in which respect it can be of interest to know when the event occurs. In certain cases, therefore, time delays can be compensated. Another requirement is that the transmission must take place with high reliability, which means that the transmission must not be sensitive to interferences in the environment in which the equipment operates. The risk of faulty connection or faulty transmission must be minimized. The communication must also operate with considerable dynamics. Upon start-up and adjustment of the equipment before a determined operating state, relatively large amounts of data are to be transmitted but without any greater requirement for short times. The contrary can apply for synchronization signals in which there is no data, but only a message that the occurrence concerned is to be transmitted. A further requirement for making it possible for synchronization to be carried out in a rapid and effective manner is that the synchronization must be capable of being sent from or by all units concerned. The respective units concerned must moreover be capable of detecting the signal, as in many cases an event within the functional run of the elements or of the textile machine requires actions from a number of units.
The use of the new micro-electronics (computer technology) means that problems arise in collecting and reaching the different pieces of information at physical boundaries or interfaces. In order to connect the units together, electrical or optical lines are used for the signal transmission. The use of the textile machine and associated connectable elements is to a great extent dependent upon how the different controlling and supervising units are connected together with the connection concerned. A complicated machine has hitherto led to extremely complicated wiring. This has meant that reconstruction of a machine has not only been a matter of exchanging a lot of units, but it has also required extensive rearrangements of wires.
There is also a requirement to optimize the weaving function in the weaving machine so that even rapid weaving runs have gentle effects or stress on different parts in the weaving machine and/or feed elements. This means, inter alia, that actions, e.g. activations and stops, of certain parts and elements are to be capable of being prepared in advance so that sudden accelerations and decelerations are avoided or high speeds can be avoided.
It is also of great interest to anticipate and measure, in a rapid, effective and supervisory manner, the yarn consumption, which in individual cases is desired to be optimum with the least possible waste.